Decking That Keeps the Space Under Your Deck Dry
AmeriDex combines cellular PVC deck boards with the Dexerdry seal to direct rain off the deck surface. For a new deck or qualifying full re-deck, the drainage is integrated into the surface as the boards are installed.
Correct pitch, flashing, fastening, and edge details matter. An open-sided space may still receive wind-driven rain; a finished ceiling, lighting, and furnishings are separate project decisions.
Request free samplesThree ways to manage water under a deck
The important distinction is where the water-management layer sits. A product described as “under-deck drainage” is not necessarily installed below the joists.
Surface-integrated decking and drainage
AmeriDex boards and the Dexerdry seal form the drainage assembly at the deck surface. The seal goes in as the boards are installed, directing surface water toward the designed discharge edge.
Separate above-joist drainage
A separate membrane or trough system can be installed above the framing and beneath the deck boards. It intercepts water before it reaches the covered framing. This is a different above-joist approach from integrating the drainage into the decking surface.
Below-joist drainage
Panels or channels installed beneath the joists collect water after it passes through the decking and framing area. Some are suitable when the existing deck surface will remain in place. They do not provide the same above-framing interception.
Choose around your project, not just a product label
- Building a new deck? Plan the decking, water path, flashing, and discharge together.
- Replacing all the boards? Have your builder assess whether the existing framing qualifies for an AmeriDex re-deck.
- Keeping the boards in place? AmeriDex is not an add-on to that finished surface. Consider a compatible below-joist option.
Budget for a complete project
Compare the same scope: decking, drainage components, fasteners, trim, framing, labor, freight, and tax. A materials allowance is not a total installed price.
Frequently asked questions
Can AmeriDex be added to my existing deck?
Not while the existing boards remain installed. A full re-deck can be considered after the old boards are removed and the framing, pitch, flashing, and other installation details are assessed.
Are all trough systems installed below the joists?
No. Some separate trough or membrane systems are installed above the joists and beneath the decking. Compare installation location, not just the words “under-deck drainage.”
Does drainage replace framing inspection and maintenance?
No. Drainage is one part of deck design. Framing condition, structural connections, flashing, inspections, and routine care still matter.
Will an open-sided patio stay dry in every weather condition?
Deck drainage addresses water from the deck surface. Wind-driven rain can still enter from open sides, and the surrounding building details must be designed appropriately.